Agricultural vehicles such as tractors, combines and the like are commonly used in agricultural fields for a variety of jobs, and construction vehicles and other large work vehicles are used for many different jobs on a variety of ground surfaces. Typically, these vehicles have large wheels with tires on which the vehicles are supported on the ground. However, for improved traction, vehicle-track module systems (or “track modules”) are used in place of wheels with tires, and such track-module systems provide a much larger ground-surface engagement area that spreads vehicle weight and tends to prevent vehicles from becoming bogged down in mud or other soft ground surfaces.
Each such track module has a large upper drive wheel connectable with respect to a vehicle axle for rotation therewith, a plurality of idler and bogey wheels, and an endless flexible rubber (i.e., rubber or rubber-like) track with a main inner surface and spaced track lugs projecting inwardly therefrom, the track extending around the wheels and being driven by its engagement with the drive wheel. Such drive wheels, of course, have circumferentially-spaced drive members engageable with the track lugs.
Over recent decades a number of significant advances have been made in vehicle track-module systems, some examples of which are the improvements described in U.S. Pat. Nos. Re 36,284 (Kelderman), 6,543,862 (Kahle et al.), and 6,536,854 (Juncker et al.), owned by ATI, Inc. of Mount Vernon, Ind., assignee of the invention disclosed and claimed herein. The drive wheel structures of the '862 and '854 patents have served to reduce track wear by reducing shearing forces on track lugs. The absence of track-interfering side structure and the resulting allowance of free adjustability of the track in its side-to-side position on the drive wheel, was part of these advances, and the improvement was important particularly given that early excessive track wear has been a primary concern when it comes to track-module technology. Nevertheless, despite the significant advances made in track-module technology, there remains a need for improved apparatus, including a need for improved drive wheels which will overcome some of the problems and shortcomings of the prior art.
Among the pressing needs with respect to track modules and track-module drive wheels is a need for much lighter equipment. In the past, operational requirements have led to drive wheel configurations which are heavy. It is recognized that lighter drive wheels would mean lesser costs and greater operational efficiencies. There has been a continuing need for lighter track-module drive wheels, and the naturally-resulting lighter track modules, without compromising on operational requirements.
Another continuing need is the need to facilitate installation of the endless rubber tracks on track modules. Past configurations have necessitated often cumbersome and, therefore, disagreeable procedures for track removal and installation. In some cases, removal and installation may require removing an idler wheel to allow removal and/or installation to proceed. There has been a continuing need to facilitate rubber track removal and installation.
Yet another disadvantage of track modules and track-module drive wheels of the prior art has been the fact that it is difficult or impossible to properly accommodate, by weighting, a particular track module to differing vehicles with differing horsepower ratings. There has been a continuing need for a track-module or track-module drive wheel that readily allows weight adjustment to accommodate a particular vehicle.
Still another problem in the field of track modules, indeed, a problem recognized by some past improvements, has been the problem of allowing the on-going clearing of mud and debris from between and along the track and drive wheel. There has been a need for a drive wheel with a high degree of openness in order to minimize the accumulation or ingestion of mud and debris. Avoiding or minimizing accumulation of mud and debris tends to increase operational efficiency and effective interaction of track and drive wheel.
Another problem has been the fact that track-module drive wheels of the prior art which have an outer band from which drive members project can in effect present varying pitch diameters during the driving interaction with track lugs. In addition, this can be exacerbated by the accumulation of mud and debris depending on the configuration of the contact surfaces between the rubber track and the drive wheel. Different pitch diameters can cause excessive track wear due to stresses within the track material. There is a continuing need for a drive wheel configuration that eliminates or minimizes variations in pitch diameter.
The aforementioned needs and problems have largely been intractable needs and problems. A solution to such problems which still retains the advantages of track-module technology and even retains the advantages of automatic track-wheel adjustability during operation that the absence of interfering drive wheel side structure has provided, would be an important advance in the art.